Apparatus, and Associated Method, for Facilitating Communication of Unfragmented Packet-Formatted Data in a Radio Communication System

1. Apparatus for facilitating communication of packet-formatted data by a mobile-host of a packet radio communication system operable pursuant to an Internet Protocol (IP) and having a network part, the mobile host for communicating with at least a first correspondent host connected in communication connectivity with the network part, said apparatus comprising: a network-positioned determiner adapted to receive an indication of initiation of communications by the mobile host, said network-positioned determiner configured to determine, on behalf of the mobile host and responsive to reception of the indication of the initiation of the communications, of at least a first packet-size into which the packet-formatted data is permitted to be formed for communication to the at least the first correspondent host, the at least the first packet size determined by said network-positioned determiner permitting communication of the packet formatted data in unfragmented form to the at least the first correspondent host.

2. The apparatus of claim 1 further comprising a notifier adapted to receive indications of determination of the at least the first packet size determiner by said network-positioned determiner, said notifier configured to notify the mobile host of the at least the first packet size permitted of the packet-formatted data to the at least the first correspondent host.

3. The apparatus of claim 2 wherein the Internet Protocol pursuant to which the radio communication system operates further comprises an Internet Message Control Protocol (IMCP) and wherein said notifier notifies the mobile host of the at least the first packet size permitted of the packet-formatted data with an Internet Message Control Protocol-formatted message.

4. The apparatus of claim 3 wherein the Internet Protocol pursuant to which the radio communication system operates comprises an IPng (Internet Protocol New Generation), and wherein the Internet Message Control Protocol-formatted message by which said notifier notifies the mobile host of the at least the first packet size permitted of the packet-formatted data comprises an llvICPng (Internet Message Control Protocol New Generation)-formatted message.

5. The apparatus of claim 4 wherein the at least the first correspondent host comprises the first correspondent host and at least a second correspondent host, wherein said network-positioned determiner determines the first packet size and at least a second packet size, the second packet size indicative of how large that the packet-formatted data is permitted to be formed for communication to the second correspondent host, indications of the first packet size and the second packet size populating the IMCPng-formatted message.

6. The apparatus of claim 4 wherein the at least the first correspondent host is identified by at least a first packet address and wherein the IMCPng-formatted message further comprises an indication of the at least the first packet address of the at least the first correspondent host.

7. The apparatus of claim 4 wherein the IMCPng-formatted message comprises a Type Field and wherein the type field is populated with a selected value to indicate the IMCPng message to contain the at least the first packet size.

8. The apparatus of claim 1 wherein the at least the first correspondent host with which the mobile node communicates comprises the first correspondent host and at least a second correspondent host and wherein the at least the first packet-size determined by said network-positioned determiner comprises the first packet size into which the packet-formatted data is permitted to be formed for communication to the first correspondent host and at least the second packet size into which the packet-formatted data is permitted to be formed for communication to the at least the second correspondent host.

9. The apparatus of claim 8 wherein the first correspondent host is accessible by way of a first link during a selected interval, the first packet size determined by said network-based determiner further associated with the first link during the selected interval, and wherein the second correspondent host is accessible by way of a second link during the selected interval, the second packet size determined by said network-based determiner further associated with the second link during the selected interval.

10. The apparatus of claim 1 wherein said network-positioned determiner comprises a Path Maximum Transmit Unit determiner, and wherein the at least the first packet size determined by said Path Maximum Transmit Unit determiner comprises a first Path Maximum Transmit Unit associated with a communication link extending to the first correspondent host.

11. The apparatus of claim 1 wherein the mobile host indicates communication by generating a domain name server inquiry and wherein said network-positioned determiner operates responsive to generation of the domain name server inquiry generated by the mobile host.

12. The apparatus of claim 11 wherein the network part of the radio communication system comprises a domain name server, wherein the domain name server inquiry generated by the mobile host is routed to the domain name server and the domain name server generates a response thereto, and wherein said network-positioned determiner is operable responsive to the response generated by the domain name server.

13. The apparatus of claim 2 wherein the network part of the radio communication system comprises a packet data service node and wherein said network-positioned determiner and said notifier are embodied at the packet data service node.

14. The apparatus of claim 1 wherein the network part of the radio communication system comprises a radio network portion and a packet data network portion, the radio network portion and the packet data network portion interconnected by a connecting entity and wherein said network-positioned determiner is embodied a the connecting entity.

15. The apparatus of claim 1 further comprising a cache for cacheing values representative of the at least the at least the first packet size, the values cached thereat selectably retrievable therefrom to notify the mobile host of the at least the first packet size.

16. A method for facilitating communication of packet-formatted data by a mobile host of a packet radio communication system operable pursuant to an Internet Protocol (IP) and having a network part, the mobile host for communicating with at least a first correspondent host connected in communication connectivity with the network part, said method comprising the operations of: detecting, at the network part, an indication of initiation of communications by the mobile host: determining at the network part, on behalf of the mobile host, and responsive to detection made during said operation of detecting at least a first packet-size into which the packet formatted data is permitted to be formed for communication to the at least the first correspondent host, the at least the first packet size permitting communication of the packet formatted data in unfragmented form to the at least the first correspondent host; and notifying the mobile host of the at least the first packet size permitted of the packet formatted data and determined during said operation of determining.

17. The method of claim 16 wherein the Internet Protocol pursuant to which the packet radio communication system is operable defines an Internet Message Control Protocol and wherein said operation of notifying comprises sending an Internet Message Control Protocol-formatted message to the mobile host.

18. The method of claim 17 wherein said operation of determining comprises performing a Discover Maximum Transmit Unit (MTU) procedure at the network part of the radio communication system.

19. The method of claim 18 further comprising the operation of cacheing the at least the first packet size determined pursuant to the Discover Maximum Transmit Unit procedure.